This invention relates to fuel compositions having improved low temperature characteristics. More particularly this invention relates to compositions comprising distillate hydrocarbon fuels having minor amounts of ester derivatives of certain branched chain monocarboxylic acids, containing tertiary amine groups. This invention is also directed to low temperature fuel additive compounds comprising said ester derivatives and to compositions containing the ester derivatives or mixtures thereof.
As is well known to those skilled in the art, diesel fuels present problems at low temperatures because of poor flow characteristics and clogging of fuel filters. Consequently there is a continuing need for means for solving these low temperature problems. The materials described herein are derivatives of specific branched-chain monocarboxylic acids which when added to a diesel fuel significantly improve its filterability and pour point.
U.S. Pat. No. 4,283,314 discloses resin compositions which employ branched chain high molecular weight ester derivatives of monocarboxylic acids. These monocarboxylic acids can be of a type commonly known as a telomer acid. U.S. Pat. No. 4,283,314 is incorporated herein in its entirety by reference.
Additives effective in lubricating oils are not necessarily effective in distillate fuels. It is also known that additives which affect pour point cannot be presumed to affect other low temperature properties such as cloud point or filterability.
U.S. Pat. No. 3,962,104 discloses lubricating oil compositions containing minor amounts of quaternary ammonium salts useful as an oil improving additive. The quanternary ammonium salts utilize a cation derived from the reaction product of one molar proportion of a tertiary amine with one or more molar proportions of an olefin and an amount of water in excess of stoichiometric.
U.S. Pat. No. 4,491,455 describes C.sub.12 -C.sub.30 linear fatty acid esters of hydroxyamines useful as a means of improving the cold flow of hydrocarbon fuel oils.
None of these prior art materials, however, utilize the specific branched chain acids or reaction products as described below or provide the breakthrough in cold flow plugging point and pour point depression of distillate fuels to ensure proper performance at low temperatures.
The additives in accordance with this invention unlike prior art cold flow improving additives, are useful in a broad range of distillate or diesel fuels. Generally speaking, prior art additives have been rather specific, being useful in one or two fuels at most.
One object of this invention is to provide additive products which will operate to lower to pour point and cloud point of hydrocarbon fuels and improve their filterability.
Another object is to provide diesel fuel oil compositions of improved low temperature characteristics.